effect of agents acting on NMDA and dopamine receptors on the responses of phrenic nerve-diaphram preparations from aged rats

Alzheimer's Dementia [AD] and Parkinsonism are common in geriatric patients. The skeletal muscles are important in the proper function of aging animals and humans. This study focuses on the influence of memantine [used for moderate to severe AD] and levodopalcarbidopa [LDICD] [a corner stone in the treatment of Parkinsonism] on responses of isolated phrenic nerve-diaphragms [IPNDs] of aged male rats. From 100 aged male albino rats twenty were untreated to study in vitro effects of memantine and LD/CD on 1PNDs. Eighty rats were divided into: Group-I [Control], Group II [oral meman tine, 1 .5mg/KgId], Group-Ill, [twice daily intraperitoneal LD/CD, 25/2.5mg/kg], Group-lV [both drugs]. After three weeks of treatment, animals were sacrificed; ten rats from each group were used to harvest IPNDs to study the effect of alIamine; 10 rats were used to measure nAchR [nicotinic acetyicholine receptor] alpha subunit mRNA by PCR. Heights of indirectly elicited contractions: 63.1 +/- 4, 6. 41.5 +/- 4.5, 70.6 +/- 4.7, 53.9 +/- 3.3mm for Groups I through IV respectively, all differences were statistically significant K0.05]. Memantine treatment caused a leftward shift of sallamine log-concentration-response curve, LD/CD caused ri.htward shift. Reversal of neuromuscular block required ier neostigmine concentrations in the memantine group it smaller concentrations in the LD/CD group. In Vitro m.antine inhibited diaphragmatic responses to indirect stam1ation. Values of nAchR alpha subunit mRNA [micro g/dl]: 1 +/- f116 [control], 0.13 +/- 0.11 [memnatine], 2.3 +/- 0.94 [LD/CD], 1.18 +/- 0.71 [both drugs] [p<0.05]. Memnatine inhibits neuromuscular transmission in vitro and with in vivo treatment. LD/CD treatment rtaaces neuiomuscular transmission. Clinical implications a1 further investigation

influence of L-carnitine among other agents on the functional recovery of the isolated rat heart exposed to hypoxic cold cardioplegia

L-carnitine, is an amino acid derivative, that has previously shown a beneficial effect on skeletal and cardiac muscle function through favorable metabolic effects. This study aims to test for a possible protective effect of L-carnitine in face of cold hypoxic cardioplegia of the isolated rat heart. Sixty male albino rats were used in this study and were divided into six study groups. Isolated rat hearts from all the study groups were exposed to hyperkalemic, hypoxic cold cardioplegia for two hours with the following changes in the cardioplegic solution: Group I served as a control group with no special additions to the cardioplegic solution; for Group II, glucose in the cardioplegic solution was increased to a concentration of 22millimole [mM] for Group III methylprednisolone sodium succinate [MPSS] was added to a concentration of 100mg per liter; Group IV received verapamil in the cardioplegic solution at a concentration of 1.1 micromol/L; Group V had L-carnitine at a concentration of 1mM and for Group VI, L-carnitine was added to the cardioplegic solution a t a concentration of 4Mm. The heart rate [HR], Dp/dt, the left ventricular developed pressure [LVDP], and rate pressure product [RPP] were recorded at baseline, and at 15 and 60 minutes after the start of re-warming. Epinephrine was given to the working hearts at doses of 0.5, 1.0 and 2.0 micromol before cardioplegia and after re-warming and the changes in cardiac function parameters in response to epinephrine were recorded. Creatine phosphokinase [CPK] was measured in samples from the coronary effluent taken before cardioplegia and 15 minutes after re-warming. The control group showed a significant reduction in all cardiac function parameters after cardioplegia and re-warming [dp/dt[max], LVDP and RPP reached 40.2%, 18.8% and 8.4% of their baseline values respectively]. Significant cardiac protection was noted in the groups exposed to glucose and carnitine. Functional recovery with glucose reached 66.2% of the baseline value for the dp/dt[max], 55.2% for the LVDP and 17.5% for the RPP [p<0.01 as compared to control]. Functional recovery with carnitine 4mM reached 98.7% of the baseline value of dp/dt[max], 89.9% for the LVDP, 48.1% for the RPP [p<0.05 as compared to all the other groups]. For carnitine at the 4mM concentration the dp/dt[max] values at the end of the experiment showed no significant difference from the baseline values. Also the percentage increase in dp/dt[max] and LVDP in response to post-cardioplegic epinephrine showed no significant difference from that recorded before cardioplegia [p>0.05]. MPSS provided only transient cardiac improvement compared to the control group, while verapamil showed no protective action on cardiac function parameters. CPK results showed significantly lower post re-warming CPK with all the tested drugs

effect of peroxisome proliferator - activated gamma agonist on resistin in obese rats with type 2 diabetes

Adipocytes are highly differentiated cells and numerous genes are expressed significantly in fat cells, resistin is an adipocytokine highly expressed in murine adipose tissue. Peroxisome proliferator-activated gamma agonists [PPAR] down-regulate resistin gene expression in adipose tissue. The aim of the present work is to clarify the effect of peroxisome proliferator-activated gamma agonist [rosiglitazone] on resistin in obese rats and obese rats with type 2 diabetes. Forty eight white albino male rats of 150-250gm average weight were randomly divided into group 1: Control group [n=8], group 2: [n=8] rats received rosiglitazone, group 3s [n=32] obese rats, this group subdivided into group 3a: Obese rats recieved the drug [n=8]. Group 3b: Obese rats after induction of type 2 diabetes, Group 3c: Obese rats with diabetes and rosiglitazone [n=8]. At the time of scarification blood was collected and samples from central fat and peripheral fat was taken. The following parameters were assessed, serum glucose, triglycerides, cholesterol, insulin, serum resistin and resistin in fats. The results of the present work showed that serum glucose, insulin, triglycerides and cholesterol were significantly higher in [group 3, group 3b] compared to the control while their levels decreased after administration of the drug [Group 3c]. As regard resistin level in serum, central fat and peripheral fat were significantly higher in [group 3 and group 3b] compared to the control however its level significantly decrease after rosiglitazone administration. Also significant correlation were found between serum resistin and serum glucose, serum triglycerides and body mass index in all studied groups. Conclusion resistin seems to play an important role in development of type 2 diabetes particularly on top of obesity and its response to [PPAR] agonist may be used to relive insulin resistance in type 2 diabetes

study on the effect of stress on serum leptin concentration in different age groups of male albino rats

The effect of two types of stress [immobilization and ether anesthesia] on the serum levels of leptin, glucose, sodium and potassium was investigated in two groups of male albino rats [young rats aged 3 months and old rats aged 24 months]. Each group was subdivided into three subgroups [each of ten rats]: Control non- stressed rats, rats subjected to immobilization and rats subjected to stress of ether anesthesia. Blood samples were collected retro- orbitally at 9-11 a.m. from overnight fasted rats and the investigated parameters were studied after 0, 5, 30 and 120 minutes from the onset of stress. It was suggested that increased leptin associated with stress means that leptin is not only an adipostatic hormone, whose function is to prevent obesity but also a stress related hormone. The process of aging and the intercurrent pathologic processes gradually eliminate the physiological reserves which are present in the younger individuals [as shown by decreased percentage of change of leptin and glucose in old rats]. This showed that old people are more vulnerable to dangers of stress than the younger persons